Differential oviposition and offspring success of gray treefrogs in the presence of an invasive fish

Abstract

Females often decide where to place their eggs or offspring based on the relative risks and benefits of a location. One trade‐off may be between ovipositing with predators and ovipositing with competitors. Many amphibians show risk‐sensitive oviposition and select oviposition sites based on offspring performance. We examined differential oviposition and offspring success by gray treefrogs (Hyla versicolor) in response to the presence of caged or free‐ranging invasive western mosquitofish (Gambusia affinis) using cattletank mesocosms as experimental ponds. Our experiment sought to answer these questions by comparing the number of eggs laid and tadpoles produced among the experimental treatments: (1) Do gray treefrogs exhibit risk‐sensitive oviposition? and (2) What is the relative importance of pre‐colonization and post‐colonization consumptive and trait‐mediated effects of western mosquitofish? Gray treefrogs laid more eggs in control and caged predator mesocosms than in free‐ranging predator mesocosms. At the end of the experiment, there were more tadpoles in control and caged predator mesocosms than in free‐ranging predator mesocosms. Proportional yield was lower in free‐ranging predator mesocosms than control and caged predator mesocosms. Eggs were laid 7–8 d earlier in control mesocosms than caged and free‐ranging predator mesocosms. Western mosquitofish therefore had a negative effect on the successful colonization of experimental ponds by gray treefrogs, most likely through direct physical interactions. Our results also suggest gray treefrogs shift oviposition preferences as the number of conspecifics reaches a threshold where competition risk outweighs predation risk. Western mosquitofish therefore have great potential to affect the distribution of gray treefrogs through pre‐ and post‐colonization effects.

Invasive Species and Amphibian Conservation

“…reduced activity, avoidance, microhabitat shift (Gamradt et al 1997, Nunes et al 2013, morphological (Nunes et al 2014), or ontogenetic, involving e.g. faster growth or development rate (Nunes et al 2019, Smith andHarmon 2019). For instance, some populations of Pelophylax perezi develop deeper tail muscles when reared in the presence of invasive crayfish, a trait that can favor faster swim and escape from predators (Dayton et al 2005, Nunes et al 2014.…”

“…For instance, some populations of Pelophylax perezi develop deeper tail muscles when reared in the presence of invasive crayfish, a trait that can favor faster swim and escape from predators (Dayton et al 2005, Nunes et al 2014. Similarly, exposure to an invasive fish will elicit faster development in tadpoles of the Gray Treefrog, Hyla versicolor, which then metamorphose more quickly and leave riskier environments sooner (Smith and Harmon 2019). Thus phenotypic plasticity can offer advantages to native amphibian species facing both invasive predators and competitors, and can help to overcome mating disruptions or habitat modifications, thus broadening the range of conditions under which they can survive (Peacor et al 2006, Caut et al 2013, Polo-Cavia and Gomez-Mestre 2014, Hossie et al 2017).…”

Legacy effects in temporally separated tadpole species are not mediated by invasive Western Mosquitofish (Gambusia affinis)

“…The density of G. affinis used was also within the range of densities of G. affinis found in local ponds (range = 1-32 m −2 ; J. E. Rettig and G. R. Smith, unpublished data). In addition, I have used similar numbers of G. affinis in other mesocosm experiments that had high survivorship of G. affinis and had impacts on tadpoles, including A. americanus (e.g., Smith et al, 2013;Smith & Harmon, 2019).…”

Amfibi sebagai model untuk mengembangkan media dan alat peraga pembelajaran sains

“…(2) perbedaan katak dan kodok, (3) lingkup genus Rana dan Bufo, (4) amfibi sebagai hewan ovipar, dan (5) siklus hidup amfibi yang memiliki fase berudu berenang bebas di air. Banyak spesies yang ovipar dan membutuhkan air sebagai tempat pemijahan (Homola et al, 2019;Smith & Harmon, 2019), namun ada juga spesies yang ovovivipar (Iskandar et al, 2014;Sandberger-Loua et al, 2016). Demikian pula dengan metamorfosis, ada berudu dari spesies amfibi yang tidak berenang bebas di habitat perairan sebelum juvenile (Iskandar, 1998).…”